Removal of sulfur compounds from hydrocarbons with alpha-sodium-sodium acetate



Pat

REMOVAL OF SULFUR COMPOUNDS FROM HY- DROCARBONS WITH a-SODIUM-SODIUM ACE- TATE Guenther Nottes and Emil Weiss, Ludwigshafen (Rhine), Germany, assignors to Badische Anilin- & Soda-Fabrik Aktieugesellschaft, Ludwigshafen (Rhine), Germany No Drawing. Filed Apr. 29, 1959, Ser. No. 809,615 Claims priority, application Germany May 9, 1958 7 Claims. (Cl. 208-232) This invention relates to the refining of hydrocarbons. The presence of sulfur compounds in hydrocarbons, such as gasolines, diesel oils, fuel oils, lubricating oils and the like, is very undesirable.

The use of free alkali metals, such as sodium and potassium, is known, inter alia, as a method for the removal of sulfur compounds from hydrocarbons. A great disadvantage in the use of free alkali metals lies in the fact, however, that these metals are readily oxidizable and also very sensitive to traces of moisture and carbon dioxide in the air.

We have now found in accordance with the invention that sulfur compounds, especially, mercaptans, can be extensively removed from liquid hydrocarbons, such as gasolines, diesel oils, jet fuels, distillate fuel oils, fractions of the distillation of coal tar and lubricating oils, by treating the hydrocarbon with alpha-sodium-sodium acetate (NaCH COONa). The compound, alpha-sodium-sodium acetate can be prepared by the process disclosed in US. Patent No. 2,850,528, granted September 2, 1958.

The amount of alpha-sodium-sodium acetate to be used in this process depends on the content of sulfur compounds in the crude.

In general, even very small amounts of alpha-sodiumsodium acetate, for example 0.01 to by weight, advantageously 0.1 to 2% by weight, are sufiicient to achieve good refining action.

The action of alpha-sodium-sodium acetate on the raw material to be refined may take place at room or at elevated temperature, e.g. up to about 350 C., preferably not higher than 250 C. Generally it is desirable that no cracking of the hydrocarbon should take place.

The pressure employed can be normal pressure up to any high pressures required in order to keep the hydrocarbon or hydrocarbon mixtures liquid at the working temperature.

The refining may for example be carried out by stirring-pulverulent alpha-sodium-sodium acetate into the hydrocarbon to be refined, to form an intimate mixture or slurry. Thus the alpha-sodium-sodium acetate will react with the sulfur compounds forming a sludge. The purified hydrocarbon can be easily separated in a conventional manner, most favorably by distillation, filtration or centrifuging.

A specially advantageous embodiment comprises the activation of the alpha-sodium-sodium acetate by the addition of a small amount of monohydric, dihydric or polyhydric alkyl, aryl, aralkyl or cyclic alcohols, e.g. methanol, isobutanol, dodecyl alcohol, glycol, glycerol, benzyl alcohol, cyclohexanol, hexylene glycol. The alcohol is added in an amount of about equal to the alpha sodium-sodium acetate, that is e.g. from 0.01 to 5% by weight.

The following examples will further illustrate this in- 1 vention but the invention 'is not restricted to these erramples. The parts and percentages are by weight;

Example 1 6 parts of NaCH .COONa are stirred into 200 parts of a doctor-positive distillate fuel oil of yellowish-green appearance (10 ccs. correspond to 0.005 cc. of AgNO according to the mercaptan determination method in C. Zerbe, Mineralole und verwandte Produkte (Mineral Oils and Allied Products), page 536, with a sulfur con tent of 0.86%. After 5 minutes, 10 parts of isobutanol are added and the Whole stirred for another 5 minutes. The isobutyl alcohol is then distilled off and recovered.

The distillate fuel oil is then distilled off in vacuo (18 mm. Hg), 195 parts of rafunate being obtained. Solid grey crusts remain in the still.

The oil treated according to this invention is waterclear, almost odorless and shows a negative doctor test. The sulfur content has diminished to 0.27%.

In a blank test without addition of NaCH .COONa, no change in the properties of the distillate fuel oil is achieved by a corresponding identical vacuum distillation.

Example 2 A mixture boiling in the gas oil range and consisting of a recycle oil from a catalytic cracking plant with a straight-run diesel oil (ratio 6:4) and which deposits a sediment when allowed to stand for a long period, is treated with 1% of NaCH .COONa according to Example 1 employing 5 parts of a technical mixture of amyl alcohols.

A waterclear product is obtained which has a color number of 0.18 in the Saybold colorimeter and a Conradson test of 0.012%. The untreated oil had a color number of 1 and a Conradson test of 0.056%.

The sulfur content is reduced by the treatment according to the invention from 0.57% to 0.24%.

Example 3 A pale green colored crude gasoline from a catalytic cracking plant and having a sulfur content of 0.11% showed an ASTM glass dish gum test of 8 mg./ ccs. 100 parts of this gasoline are stirred with 1% of NaCH- COONa in an autoclave under a pressure of 3 excess atmospheres for 30 minutes at 100 C. From the resulting reaction mixture, the gasoline is distilled oif. 96 parts of a refined product are obtained which shows an ASTM gum test of 1.6 mg./ 100 ccs. and a sulfur content of 0.03%. The product was Waterclear.

We claim:

1. A process for the removal of sulfur-containing impurities from a crude liquid hydrocarbon which cimprises treating the hydrocarbon with alpha-sodium-sodium acetate (NaCH .COONa).

2. A process as claimed in claim 1 which comprises treating the hydrocarbon with alpha-sodium-sodium acetate in the presence of an alcohol as an activator.

3. A process as claimed in claim 1 which comprises treating the hydrocarbon with alpha-sodium-sodium acetate in an amount of 0.01 to 5% by weight.

4. A process as claimed in claim 3 which comprises treating the hydrocarbon with the alpha-sodium-sodium acetate in the presence of an alcohol in the amount of 0.01 to 5% by weight as an activator.

5. A process for the removal of sulphur-containing impurities from a crude liquid hydrocarbon which comprises contacting the crude hydrocarbon with from 0.01 to 5% by weight of alpha-sodium-sodium acetate for reaction with sulphur compounds to form a sludge, and separating the sludge from the hydrocarbon.

6. A process as claimed in claim 5 wherein the crude Pa t ented -Octu2s; 1960 hydrocarbon is contacted with about 0.1 to 2% by weight References Cited in the fil of this patent of alpha-sodium-sodium acetate.

7. A process as claimed in claim 5 wherein the crude UNITED STATES PATENTS hydrocarbon is contacted with alpha-sodium-sodium ace- 1,317,868 Ellis Oct. 7, 1919 tate in the presence of an alcohol in the amount of 0.01 5 2,164,851 Yabrofi et al. July 4, 1939 to 5% by weight as an activator. 

1. A PROCESS FOR THE REMOVAL OF SULFUR-CONTAINING IMPURITIES FROM A CRUDE LIQUID HYDROCARBON WHICH CIMPRISES TREATING THE HYDROCARBON WITH ALPHA-SODIUM-SODIUM ACETATE (NACH2COONA). 